1. Field of the Invention
This invention relates to a manufacturing history management system which is suitably applicable to a vehicle production line or the like.
2. Description of the Prior Art
FA (factory automation) techniques have brought great results of the product quality improvement, manufacturing cost reduction and productivity improvement to the fields of manufacture. In a production system, in which this kind of FA technology is introduced, the operations of conveying parts to be assembled, control of the assembling and manufacture of the product are all carried out under computer control. More specifically, under the computer control the parts to be assembled are successively conveyed to individual assembling stations, to which control data determined in correspondence to product specifications are supplied. In this way, the desired product is automatically produced without need of cumbersome manual labor. Further, in a process requiring stringent control, the result of operation carried out in each station, for instance the degree of make-up of a bolt, is measured by a sensor or the like, and the result of measurement is checked whether it is coincident with a common setting that is prepared for each product or each part. Only work which has passed the check is fed to the next step. The operations and monitoring thereof are thus effected together for stable production of high quality product.
Meanwhile, the results of monitoring of the contents of operations in the assembling stations in the above production system, although they are often utilized while the product is being manufactured, encounter less occasions to be utilized after the product has been completed and shipped. That is, the results of monitoring have not been managed by taking their utilization efficiency into considerations. Depending on manufactures, however, it is possible in actual practice that information about the history of manufacture of each product becomes necessary after the shipment of the product. For example, a vehicle which has been delivered from a vehicle manufacturer to a purchaser may subsequently get into a trouble. In such a case, it is advantageous in the troubleshooting that there is stored history of the vehicle manufacture, such as the degree of make-up of each bolt in the vehicle. Further, precious technical data for further improving the durability of the vehicle is obtainable by recovering a discarded vehicle, checking the state of each part of the vehicle and collating the result of check with the history of the vehicle manufacture. Thus, for the manufacturer it has been very useful to obtain the history of manufacture of the product. When it is intended to obtain the manufacture history of each product, however, the operation that is performed on each product in each step in the production line has to be monitored at all times. Usually, the production line has many steps. Therefore, if the operation in each of these steps is to be monitored for each product, it dictates enormous burden for the monitoring. If a host computer for controlling the production line also has the role of monitoring the operation content in each step, a considerable portion of its capacity is expended for the monitoring of the operation content, thus resulting in impediment of the effective management of the production line. Heretofore, there has been no effective means for solving this problem, and therefore a system which is effective in view of the above sense has not been realized.
It is an object of the present invention is to provide a manufacturing history management system, which can overcome the above drawback and can collect and manage history of manufacture of products.